Movable platform unit for a boat particularly for hauling and launching tenders and the like

ABSTRACT

A movable platform unit ( 1 ) for a boat (B), in particular for launching or hauling out a tender or the like, includes a base portion ( 2 ) secured to the boat (B) and at least one swing arm ( 32   a,    32   b ), pivoted at one end onto the base portion ( 2 ) and at the other to a load platform ( 3 ). The swing arm ( 32   a,    32   b ) can be rotated by a first drive member ( 57 ) secured thereto and rotatable about the axis (x) about which the swing arm ( 32   a,    32   b ) is pivoted on the base portion ( 2 ). Alignment means ( 67, 68 ) are provided for connecting the load platform ( 3 ) to a second drive member ( 65   a ) secured to the base portion ( 2 ) and coaxial with the axis (x) about which the swing arm ( 32   a,    32   b ) is pivoted on the base portion ( 2 ) so as to enable the platform ( 3 ) to maintain a constant inclination to the base portion ( 2 ) during rotation of the swing arms ( 32   a,    32   b )

The present invention relates to a movable platform unit for a boat,intended in particular for launching or hauling out a tender or similarwater craft, of the type described in the preamble to Claim 1.

It is known that certain categories of vessels, such as yachts, usesmall cranes, generally positioned in the stern, for lowering into thewater or hauling out small tenders.

The use of movable platforms, which can be lowered beneath the surfaceof the water for launching a tender, is also known in the art. Germanpatent DE 19 963 057 and German utility model DE 29 922 612, forexample, describe a platform unit of the type referred to above. Thisplatform unit has a plurality of arms which move in pantograph style,giving the platform enough range of movement that it can also be used asa gangway for passengers to move from one vessel to another.

The versatility of this known platform unit is fairly limited however:the range of movement which can be achieved only enables the platform toreach a landing stage or boat deck having heights which are not muchdifferent from that of the vessel on which it is installed. In addition,the platform cannot be retracted, meaning that is always on view evenwhen not in use. This is a disadvantage from an aesthetic point of view,especially in the case of a yacht, wherein such an aspect is often ofgreat importance.

These problems are overcome according to the invention by providing aplatform unit having the characteristics claimed in Claim 1.

Preferred embodiments of the invention are described in the dependentClaims.

In particular, in some of these embodiments, the platform unit hasautomatically adjustable steps, which provide easy access to and fromthe vessel, whatever the height of the movable platform. The platformunit of the invention can therefore also be used as a ladder forswimmers to get in and out of the water.

These and other objects will become more apparent from the detaileddescription of a preferred, but non-limitative embodiment of theinvention, provided with reference to the appended drawings, in which:

FIG. 1 is a perspective view of a platform unit for a vessel accordingto the present invention, shown in a first operating position;

FIG. 2 is a perspective view of the platform unit of FIG. 1 in a secondoperating position;

FIG. 3 is a perspective view of a structure of the platform unit of FIG.1 in the second operating assembly;

FIG. 4 is a plan view from above of the structure of FIG. 3 in the firstoperating position;

FIG. 5 is a schematic side elevation view of a platform unit accordingto the present invention;

FIG. 6 is a sectioned view of the structure of FIG. 4 taken on the lineVI-VI of this Figure;

FIG. 7 is a sectioned view of the structure of FIG. 4 taken on the lineVII-VII of this Figure;

FIG. 8 is a sectioned view of the structure of FIG. 4 taken on the lineVIII-VIII of this Figure; and

FIG. 9 is a view of a vessel fitted with a platform unit of theinvention.

With reference to FIG. 1, a platform unit 1 according to the inventionis shown, which is intended to be mounted preferably in the sternportion of a vessel. The platform unit 1 includes a base 2, with amovable platform 3 pivoted thereon and shown in a closed position inFIG. 1. The base 2 can have means (not shown) for enabling the unit 1 tobe fixed to the structure of the vessel or, in an alternativeembodiment, can be incorporated into the structure of the vessel.

With reference to FIG. 2, the platform unit 1 is shown in its fullyextended position. The base 2 of this unit has a cavity 21 for housingthe movable platform 3. The cavity 21 is shaped so that, in its closedposition, the platform 3 precisely fits the overall shape of the base 2,as illustrated in FIG. 1. The cavity 21 also houses a pair of fixed arms22 a, 22 b.

As can be seen better in FIG. 3, the fixed arms 22 a, 22 b haverespective fixing plates 23 a, 23 b for mounting them on the base 2 byconventional fixing means, such as bolts, for example. Swing arms 32 a,32 b are connected to the distal ends of the fixed arms 22 a, 22 b,respectively, so that they can turn in a vertical plane, perpendicularto the overall plane of the base 2 of the platform unit 1 (each in thedirection indicated by the arrow A). The swing arms 32 a, 32 b and aplurality of steps 35 connected thereto form a ladder, which isorientable in a vertical plane. Each step 35 is turnable about its ownlongitudinal axis relative to the swing arms 32 a, 32 b (in thedirection shown by the arrows B1). The top step 35 a is secured to thebase 2 of the platform unit 1 by a pair of brackets 36 a, 36 b fixed byone end to the ends of the step 35 a and by the other to the base 2itself.

The distal ends of the swing arms 32 a, 32 b are finally connected by across member 37, also turnable about its longitudinal axis relative tothe swing arms 32 a, 32 b (in the directions indicated by the arrowsB2). A pair of supports 38 a, 38 b is fixed one to each end of the crossmember 37, being thus pivoted on the swing arm 32 a, 32 b. It can beseen that the supports 38 a, 38 b are able to turn in a vertical planerelative to the swing arms 32 a, 32 b (in the sense indicated by thearrows B2) until they reach the closed position shown in FIG. 4, foldedalong the arms 32 a, 32 b. The supports 38 a, 38 b are provided formounting the movable platform 3, as shown in FIG. 2.

The diagram shown in FIG. 5 better illustrates the operation of theplatform unit of the invention. This diagram consists of a side view ofthe platform unit 1 mounted on a boat, generally indicated B. Anoperating unit 50 includes a pair of single-acting hydraulic cylinders51, 52, having respective rods 51 a, 52 a (slidable in the directionindicated by the arrows C1 and C2 respectively) secured to the end of adrive chain 55. The drive chain 55 passes over an operating pulley 57.As can be seen better from FIG. 6, this pulley 57 is keyed onto a shaft57 a which is secured to the swing arm 32 a. The pulley 57 and the swingarm 32 a to which it is attached are pivoted on the bracket 36 a so asto be able to turn about the axis-x of the pulley 57 (along the arrowsA). In order to increase the angle over which the chain 55 contacts thepulley 57 and to avoid non-axial stress on the cylinder rods, chainguides 58 are provided, shown in FIG. 5.

The operating unit 50, controlled by a hydraulic control unit whichincludes a solenoid control valve 59, is at least partly enclosed withinthe fixed arm 22 a (see FIG. 2 by way of example), which is hollow forthis purpose. The swing arm 32 b naturally also has an operating unit,identical to that described above and controlled by the same controlunit. The solenoid control valve 59 is connected separately to thecylinders 51, 52 through respective piloted unidirectional valves 59 a,59 b, and is operable to control selectively either the upper cylinders51 or the lower 52. Inserted into the bottom of the cylinders 51, 52,the piloted non-return valves 59 a, 59 b, selectively block flow of thehydraulic fluid, enabling the platform 3 to be locked into any position.

The rod-side chambers of the upper cylinders 51 and those of the lowercylinders 52 are in communication by means of a passage 59 c, thefunction of which will be described later, Unidirectional flow-regulatorvalves 59 d and 59 e connect the solenoid valve 59 with the non-returnvalve 59 a and the non-return valve 59 b respectively.

The platform unit of the invention makes it possible to turn the swingarms 32 a, 32 b through a maximum angle of around 240° or even more fromthe closed position, in which the said arms 32 a, 32 b are lying flat onthe base 2 of the platform unit 1, to the fully open position dependenton the particular arrangement of the axis x about which the arms 32 a,32 b are pivoted.

The swing arm 32 a, which is also hollow, contains an alignment unit 60for ensuring that the steps 35 and the platform 3 retain theirorientation relative to the base 2 during rotation of the swing arms 32a. To this end, each step 35 (as shown in FIG. 7) is secured to arespective pulley 65, by means of the shaft onto which each pulley 65 iskeyed. The shaft of each pulley 65 passes through the inward sidewall ofthe swing arm 32 a. This means that the pulley 65 and its associatedstep 35 are pivoted on the swing arm 32 a, so as to be rotatable aboutan axis parallel to the axis x. With reference to FIG. 6, the step 35 ais secured to the respective pulley 65 a by means of the shaft 65b ontowhich this pulley 65 a is keyed. The shaft 65b of the pulley 65 a passesthrough the inward side wall of the swing arm 32 a, coaxially with, butindependently of the shaft 57 a of the pulley 57 and is secured to thebracket 36 a, thus ensuring that it remains immobile during rotation ofthe swing arm 32 a. A final pulley 67, similar to the aforementionedpulleys 65 and 65 a, is secured to the cross-member 37 (shown in FIG.3). With reference to FIGS. 5 and 8, an alignment chain 68 passes overthe pulleys 65, 65 a and 67 so as to ensure that the pulleys all rotatein unison.

With reference to FIG. 8, in which only the swing arm 32 a has beenshown for the sake of simplicity, upper and lower tensioner devices 69a, 69 b make it possible to increase the contact angle of the chain 68over the pulleys 65, 65 a, 67 and thereby to keep tension constant. Thetensioner devices 69 a, 69 b preferably consist of a plurality ofrollers carried on corresponding adjustable eccentric pins 71 a. Theeccentric pins 71 a associated with the upper tensioner devices 69 a areconnected to each other by a chain 72 a which ensures that the positionof the platform 3 and the steps 35 is adjusted evenly, by applying thesame deformation to each free portion of the alignment chain 68. Thelower tensioner devices 69 b are also connected by a chain 72 b, in anarrangement which is the same as that just described and so will not bedescribed here.

With reference to FIG. 5, operation of the platform unit of theinvention when in its initial, closed position will now be described. Anoperator causes the hydraulic control unit to introduce fluid throughthe bottom of the upper cylinders 51. The oil contained in the rod-sidechambers of the upper cylinders 51, flows through the passage 59 c andinto the rod-side chambers of the lower cylinders 52. The rods 52 aslide in the cylinders 52, drawing along the lower branch of the chain55 and thereby causing the pulley 57 to rotate. As a result, the swingarms 32 a, 32 b rotate, moving upwards and away from the closedposition. Once the swing arms 32 a, 32 b have reached a verticalposition, this movement is controlled by the one-way flow-regulatorvalve 59 e, arranged in the hydraulic unit, which provides sufficientcounter-pressure on the hydraulic return duct to exert a braking actionon the platform 3, which is descending on the supports 38 a under theweight of the structure and of any load carried on the platform 3. Anadditional one-way flow regulator 59 d is arranged on the other branchof the hydraulic supply system and carries out the same function ofdescent controlling, when the movement is in the opposite direction,that is when the platform is being returned to its closed condition.

As described above, the rod-side chambers of the upper cylinders 51 andlower cylinders 52 are in free communication with each other, andconnectable to an external control unit by means of respectiveconnectors fitted with unidirectional valves 59 a, 59 b: by introducingpressurized fluid through these valves, it is possible to compensate forplay in the chain 55 and to ensure that this chain 55 is pre-tensioned,thereby avoiding any abrupt acceleration at the instant of change ofdirection of the resisting moment, due to the load on the platform 3(that is in a condition in which the swing arms 32 a, 32 b arevertical).

In a preferred embodiment of the invention, the rod-side chambers of theupper cylinders 51 and lower cylinders 52 can be in communication with acompensation chamber 80, with a manually controlled piston (by means ofa nut and a screw, for example) for compressing the oil inside therod-side chambers of the cylinders 51 and 52 so as to enable any slackin the chain 55 to be taken up by a simple manual operation, without itbeing necessary to connect a control unit.

When the fluid supply is interrupted, the platform 3 is stopped at therequired height and is kept there by the non-return valves 59 a, 59 bwhich prevent the fluid from flowing out of the upper cylinders 51,thereby maintaining tension on the chain 55. In order to return theplatform 3 to its closed position, the cylinders 51, 52 are operated inreverse order.

The alignment unit 60 makes it possible to keep the steps 35 and theplatform 3 in a constant horizontal position all the time while theswing arms 32 a, 32 b are moving, thanks to the alignment chain 68secured to the fixed pulley 65 a, which keeps the pulleys 65 and 67aligned thereto.

It can easily be seen that by lowering the platform 3 so that the swingarms 32 a, 32 b are in their fully open position (as shown in FIG. 9),it is possible to lower the platform 3 beneath the surface of the water,making it possible to launch or haul back on board a tender or similarcraft associated with the boat B, while the steps 35 give swimmers easyaccess to the water. It is also possible to vary the position of theplatform 3, so as to access quays of different heights, while the factthat the platform 3 and the steps 35 always remain horizontal makes iteasy to board or disembark from the boat B. In addition, the fact thatthe platform 3 always remains horizontal while it is being moved, giveseasy access to people who are in any way disabled and also makes it easyto load heavy objects.

1. A movable platform unit (1) for a boat (B), in particular forlaunching or hauling out a tender or similar craft, which includes abase portion (2), secured to the boat (B), and at least one swing arm(32 a, 32 b) pivoted by one end to the said base portion (2) and by theother to a loading platform (3), the said at least one swing arm (32 a,32 b) being rotatable by a first drive member (57) secured thereto androtatable about the pivoting axis (x) of the swing arm (32 a, 32 b) ontothe base portion (2), alignment means (67, 68) being provided forconnecting the said platform (3) with a second drive member (65 a) fixedto the said base portion (2) and coaxial with the pivoting axis (x) ofthe swing arm (32 a, 32 b) on the base portion (2), in such a way thatthe platform (3) is enabled to remain at a constant inclination to thesaid base portion (2) during rotation of the said at least one swing arm(32 a, 32 b), characterised in that the said first drive member (57)includes a pulley element securely fixed to the said at least one swingarm (32 a, 32 b) and operable to be rotated by first chain drive means(55), the said chain drive means (55) and the said pulley element (57)being enclosed within at least one hollow fixed arm (22 a, 22 b)provided in a cavity (21) of the base portion (2), and the said at leastone swing arm (32 a, 32 b) being pivoted to the distal end of the saidat least one fixed arm (22 a, 22 b) in such a way that the swing arm (32a, 32 b) can assume a closed position, in which it lies flat in thecavity (21) of the base portion (2).
 2. A platform unit according toclaim 1, in which the said second drive member (65 a) includes a pulleyelement secured to the said base portion (2), and the said platform (3)is secured to a further pulley element (67), the said secondtransmission member (65 a) and the said pulley element (67) beingconnected by second chain drive means (68) so as to be rotatabletogether in relation to the swing arm (32 a, 32 b).
 3. A platform unitaccording to claim 1 or 2, in which the said at least one swing arm (32a, 32 b) has a plurality of step elements (35, 35 a) mounted along itslength for facilitating access to the platform (3) by users.
 4. Aplatform unit according to claim 3, in which the said alignment means(67, 68) connect the said load platform (3) and the said second drivemember (65 a) to third drive means (65), secured to the said pluralityof step elements (35, 35 a) and rotatable about axes parallel to theaxis (x) about which the swing arm (32 a, 32 b) is pivoted on the baseportion (2) in such a way as to enable the said plurality of stepelements (35, 35 a) constantly to maintain substantially the sameinclination as the said platform (3) during rotation of the said atleast one swing arm (32, 32 a).
 5. A platform unit according to claim 4,in which the said third drive means (65) include a plurality of pulleyelements, each secured to a respective step element (35), the saidsecond chain drive means (68) also connecting the pulley elements (65)of the step elements (35) to the pulley element of the second drivemember (65 a) in such a way that these pulley elements are rotatabletogether relative to the swing arm (32 a, 32 b).
 6. A platform unitaccording to any preceding claim, in which the said base portion (2) isadapted to be fixed to the structure of a boat (B).
 7. A platform unitaccording to claim 1, in which the said first chain drive means (55) iscapable of being driven alternately by first and secondhydraulic-cylinder control means (51, 52), operable to be controlledselectively by solenoid valve means (59).